Improvement in fluid-pressure brake apparatus



2 Sheets-Sheet 1. G. WESTINGHOUSE, Jr.

Fluid-Pressure Brake Apparatus. No. 218,149. w Patented Aug. 5, 1879.

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G WESTINGHOUSE, Jr Fluid-Pressure Brake Apparatus. No. 218,149. Pa'tented Aug. 5,1879.

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UNITED STATEs PATENT OEEICE,

GEORGE WESTINGHOUSE, JR., OF PITTSBURG, PENNSYLVANIA.

IMPROVEMENT IN FLUID-PRESSURE BRAKE APPARATUS.

Specification forming part of Letters Patent No. 218,149, dated August 5, 1879; application led June 7, 1879.

To all whom 'it may concer/n:

Be it known that I, GEORGE WESTING- HOUSE, J r., of Pittsburg, county of Allegheny, State of Pennsylvania, have invented or discovered a new and useful Improvement in Fluid- Pressure Brake Apparatus; and I do hereby declare the following to be a full, clear, concise, and exact description thereof, reference being had to the accompanying drawings, making a part of this specification, in whichlike letters indicating like parts- Figure l, Sheet 1, representsa vertical section of an escape-valve which I employ for regulating the pressure of the brake-shoes on the wheels, more particularly in. the manner represented in Figs. 2, 3, 4, and 5, of which Fig. 2, Sheet 2, is a side view; Fig. 3, Sheet 2, a plan; Fig. 4, Sheet l, an end view of part of the carframe and running-gear with my improvement applied thereto; and Fig. 5, Sheet l, is a section, to an enlarged scale, of the governor which I employ and the escape-Valve worked by it.

In various patents heretofore granted to me Ihave described systems of workin g the brakes of railway-trains by duid-pressure communicated throughout the train by suitable pipes, and more particularly a system according to which air compressed by a pump into a main reservoir on the locomotive supplies auxiliary reservoirs on the several cars of the train, and the store ofv power retained in these reservoirs is employed to act in cylinders upon pistons connected directly or indirectly with the brakelevers, so as simultaneously to apply the several sets of brakes when desired, or in case of accident to the train.

My present improvement relates, chiefly, to certain additions to duid-pressure brake apparatus, whereby it is rendered more effective, as also more uniform and regulanrlin its action, thereby making the system of operating therewith more complete and certain.

In carrying it out I connect with some one of the air or other fluid-pressure conduit-pipes an escape-valve, by which to lower the pressure when desired, and open and close such valve automatically, according to the varying speed of the train, as a greater or less reduction of pressure may be desired, by the use of a governor device operated from the axle or other revolving gear of the train, such action of the governor and escape-valve being independent of the more or less open position of the cock or other device by the use of which the brakepressure is applied.

It will be remembered that in the class of brakes now under particular consideration, known sometimes as the automatic brake,7 the air-pressure stored up in the auxiliary reservoir is brought into action on the pistons or other movable parts o'f the brake-cylinders or diaphragms by reducing to a greater or less degree the Huid-pressure in the conduit-pipes.

In Fig. 1 I have shown a valve box or case, Q, which has four apertures. Iwo of them, q and q', communicate with the brake-cylinder, the valve-box being introduced into the branch pipe by which the cylinder is supplied. The third aperture, r, opening to the outer air, is fitted with a valve, s, to the stem s1 of which is attached a exible diaphragm, s2, secured at its edge to the valve-box.

The valve has projecting from it a short rod, which works as a guide in the aperture r, and this rod is notched or flattened on one side, as shown at W, so as to give passage through the aperture, varying in area as the valve moves.

The fourth aperture, t, communicates with a pipe, t1, containing iiuid under pressure, which is regulated by a centrifugal governor.

The valve, with its diaphragm s2, is pressed down by a spring, s3, adjusted to a pressure less than that required in the brake-cylinder, and it is also pressed down by the iiuid in the pipe with which t communicates. As long as the pressure of the spring s3 along with that in t exceeds the pressure in the brake-cylinder the aperture r remains closed by the valve; but when the pressure in the brake-cylinder exceeds that due to the spring and the fluid in t acting along with it, then the diaphragm s2 is forced upward, raising the valve s, and s0 opening the aperture r and allowing air to escape until the pressure in the brake-cylinder becomes reduced to balance the combined pressure of the spring s3 and the iiuid in the branch t.

The pressure of the fluid in t is varied during the action of the brakes, so as to be greatest when the wheels are moving rapidly and to decrease as they revolve more slowly, it having been found that the brake-shoes exert greater friction on wheels when they are slowly revolving than when they are rapidly revolving, and consequently less pressure is required in the brake-cylinder as the train is comin g to rest.

For the purpose of varying the pressure in t in accordance with the speed of the train, I employ either of two arrangements or constructions.

According to the one the branches t of the several escape-valves throughout the train are all in communication with a pipe, t, supplied through a small orifice, t2, (made therein at at any suitable point,) with compressed air from the reservoir on the locomotive, and provided with an escape-valve, which is held to its seat by a centrifugal governor driven by one of the running axles, as hereinafter described with reference to the other construction.

WVhen the train is moving rapidly, the governor, revolving rapidly, keeps the escapevalve of the pipe closed., so that considerable pressure is maintained in the pipe; but as the train moves more slowly the governor, also hecoming retarded, allows the escape-valve of the pipe to open more or less, and thus the pressure in the pipe, and, consequently, that acting 011 the diaphragm s2, becomes reduced.

According to the other construction, instead ot' regulating the pressure in t by means of a pipe communicating throughout the train and having the pressure in it controlled by one governor, I combine the escape-valve of each brake-cylinder with a local governor driven from one of the running axles of the car itself, such construction being represented in Figs. 2, 5.

The brake-lever A is worked by the rod a., connected in the usual way to the piston of the brake-cylinder, from which cylinder there is communication, by a pipe, B, and tubular link C, to the interior of the escape-valve under its diaphragm s2. The pipe B is bentinto one or more coils at b, to allow of a little flexure when the link C is moved.

To the lower end of the link C is fixed a horizontal axle, E, forming a bearing, on which the governor revolves. This governor consists of a hollow casing, F, having on its periphery aring,f, of caoutchouc, leather, wood, or other suitable material of like nature, and having mounted within it two bent levers, G, with weights g at their inner ends. The short arms of the levers G bear on the end of a central sliding rod, H, which is prevented from revolving by a stud, h, projecting into a slot of the rod. The inner end of the rod II bears against the stem sl of the escape-valve, which is similar in construction and arrangement to that described above with reference to Fig. 1, having an opening at r to the outer air.

The link C, with the governor, is drawn toward the carriage-axle I by a spring, i; but so long as the brakes are olf, as shown in Fig. 2, the periphery j' of the governor-casing is kept away from contact with the axle l by a hooked bar, a', which is fixed to the rod a and is bent partly round the link C.

When the rod a advances so as to put on the brakes the link C is permitted to be drawn by thc spring t' till the periphery f of the governor-drum is brought in contact with the axle l, and thereby caused to revolve. While it revolves rapidly, its weights g, tending by centrifugal force outward, cause the rod H and the stem of the escape-valve to be pressed forward, closing the escape-aperture r; but when, on the train moving more slowly, the governor is driven with less velocity, the pressure, acting under the diaphragm s, overcomes the centrifugal force of the governor, so as to unseat the valve and allow escape by the aperture r, thereby causing the pressure acting in the brake-cylinder to be reduced, and conscq uentl y diminishing the pressure of the brakeblocks upon the wheels as they revolve more slowly.

I am aware that a governor device has been combined with the running axle of a train, and by means of a slide-valve with the charging and discharging pipes of a steam-brake apparatus, in such manner that with the varying` speed of the train the steam-pressure was automatically admitted to and discharged from thc brake-cylinder, so as to prevent the train from running at any time at greater than a predetermined speed. My present invention differs from this in the fact thatthe action of the governor is independent of the more or less open position of the charging-cock, which latter is under the control of the engineer, so that he can apply the brake whether the train be running fast or slow, and the function of the governor and escape-valve is simply to vary the effective force of such fluid-pressure as the engineer may thus admit to the brake-cylinders, while the train may gradually slacken its speed.

I claim herein as my invention- 1. A valve-case, Q, having ports q q', for connection in the line of communication to the brake-cylinder, a port, r, leading to the external air, a diaphragm (or equivalent piston) valve for opening and closing the escape-port by variations of air-pressure, and a spring, s3, for providing an excess of pressure on one side, substantially as set forth with reference to Fig. 1.

2. 1n combination with the conduit-pipes and brake-cylinder of a Huid-pressure brake apparatus, a fluid-pressure escape-port opened and closed by a governor acting independently of the more or less open position of the fluid-pressure charging device or devices of the apparatus, substantially as set forth.

3. A governor operating the escape-valve of a uid-pressure brake, such governor being rigging for shifting the governor one Way, and. a. spring for shifting it the other Way, substantially as set forth.

In testimony whereof I have hereunto set my hand.

GEO. WESTINGHOUSE, TR.

Witnesses:

CHAs. BERKLEY HARRIs,

17 Gt'aeeehureh Street, London. JOHN DEAN,

17 Gmeeehweh Street, London. 

